The Radiation Therapy Oncology Group is a cooperative group of radiation therapy research and clinical centers which conducts joint clinical investigations. The group undertakes clinical trials and other cooperative studies in an endeavor to advance knowledge in the curative and palliative management of cancer with radiation therapy. Through the collaboration of the radiotherapy centers in the Radiation Therapy Oncology Group it is possible to provide an adequate number of patients to answer significant questions in the treatment of cancer, not possible on the basis of the number of patients seen in any one institution. The Office of Protocol Development of the RTOG is located at the University of Rochester Cancer Center, Division of Radiation Oncology and has the responsibility for coordinating the development of and disseminating information on all protocols. The Division of Radiation Oncology Physics Section, over the past three years, has produced ten Treatment Planning Guidelines covering fifteen sites, in order the maximize standardization of treatment planning throughout the RTOG. These booklets have been collated into a bound volume entitled Standard Treatment Plans. This group will make possible the collection of long-term data by the accession of patients to protocols, the implementation of retrospective and prospective registries and data banks, and the use of pilot studies testing more experimental treatments.